Two-stage fuel unit



Nov. 3, 1953` w. R. KIEFER 2,657,632

Two-STAGE FUEL UNIT Filed Feb. 1s, 1951 5 sheets-sheet 1 wv 1 www l 1 ..w A, r NN Q WN WN .Q l I NN .llF//J/ 1 Bv A 1 1 mWWNQQmwLINmV n QN wm am QN *ma @w N .1. NN 1 m @W N TiKN r 11?, XVIF s NOV- 3, 1953 w. R. KIEFER 2,657,632

Two-STAGE FUEL UNIT Filed Feb. 16, 1951 5 Sheets-Sheet 2v STSTHGE ZNDSTHEE NOV 3, 1953 w. R. KIEFER 2,657,632

Two-STAGE FUEL UNIT Filed Feb. 16, 1951 5 Sheets-Sheet 3 Patented Nov. 3, 1953 William Ray Kiefer,

Rockford, Ill., `assigner to Sund'strand Machine Tool Co., a corporation of' Illinois Application. February-16, 19751,l Serial No.. 211,244

'8 Claims. (Cl. 10S-.45)

This .invention relates to apump and more particularly .to a two-stage oil burner pump unit in which a rst stage pump is effective to draw oil into and from a reservoir in theA casing of the unit and from which it is supplied by gravity to a second stage pump.

, is the general object of the vinvention to provide a new and improved two-stage oil burner pump unit.

Another object is to provide a two-stage pump unit embodying a reservoir, a .second stage pump having its inlet connected to a .lower portion of said reservoir, and a first stage pump with its inlet connected to the upper portion of the reservoir and its outlet connected back to the supply tank.

A further object of the invention is to provide a pump of the type described in the preceding paragraphs so arranged that the first stage pump discharges into the supply tank while the excess from the second stage pump is returned to Vthe Y reservoir in order to minimize the circulating oil supply for both pumps.

Another object of the invention vis to provide a two stage pump unit in which the inlets of both pumps are connected in parallel so that the first stage pump operates to assist the second stage pump to pull oil into the pump reservoir.

Another object of the invention is to produce a two stage pump in `which the 'iniet for the iirst stage is located near the top of the reservoir .and the inlet for the second stage is located near lthe bottom of the reservoir and in which the rst stage sucks oil into the reservoir while simultaneously removing air and excess oil therefrom whereby the second stage pumps only oilfree of entrained air and vapor.

Other objects will become readily apparent from the following detailed description taken :ln connection with the. accompanying drawings, in which:

Y' Fig. 1 is a longitudinal central section through a preferred form of the invention;

Fig. 2 is a section approximately along the line 2-2 of'Fig. 1;

Fig. 3 is a diagrammatic view fof thefuel circuit, and Y Fig. 4 is a view like Fig. 3 oi a modiiied form of circuit.

While there is shown in the drawings andl herein described in detail two embodiments of the nvention,;it is to be understood that the'invention is not limited tothe specic forms disclosed butv includes all modications and alternative constructions falling within the .spirit and scope of theappended claims.

'port 43 :lor-med in the plates '44 4which extends downwardly In the forms chosen .for purposes of' disclosure, the invention comprises generally a two-part casing l0, H, a rst pumping device or means 12'-, a second pumping device or means I3', a drive shaft I4, av mechanical seal 1'5 for the drive shaft, a strainer I6, and a control `valve mechanism llil. It 'is contemplated that the shaft I-i' will be connected by suitable means to a driving motor (not shown), that an inlet port II8 will be connected to la source of duid supply. and a discharge port I9 to a vburner nozzle. The casing parts 'are formed to provide a ysi'xbs'ta-ntially cylindrical chamber or recess 2-0, in which the pumping devices 12 and vI3 and strainer i6 are positioned for purposes hereinafter more fully described.

As illustrated herein, the casing part 10 tis in the form of a body member which is also used for ysupporting the fuel unit. Preferably, this member is formed vwith supporting lugs 2l having bolt receiving apertures 22 (Fig. 2). The part II is in the form of a closure or cover and 'is bolted to the part Hl by means of a plurality of screw devicesV 23.

The pumping devices l2 and I3 comprise end plates 24 and 25, an intermediate plate 26 and annular spacing members '21 and 28. A rst stage pump comprising a roller or pinion 29 and an intermeshing toothed ring 30 are operable in the chamber formed intermediate the plates '24 and 26, and -a Vsecond stage pump comprising a roller or pinion 3| and a toothed ring 32 4operate inthe chamber formed intermediate the plates 25 and 25. The rollers '29 and 34 are provided with driving pins 33 and 34 respectively which inter-engage with a key-Way 3'5 in the drive shaft lll vwhen the pumping unit is assembled.

A crescent 316 for the first `stage pump is suitably secured tothe plate 2l, and a crescent 31 is secured to the end plate 26 for the second stage pump. y

VThe endv plate '24 contains an inlet port di! which extends'througli the periphery of Ythe plate 2i forv supplying fluid to the Yirst stage pump. vThe intermediate plate 12e has an arcuate discharge cavity 42 which is connected with channel 2t, 23 and 25. Oil 1in the channel port d3 is .directed into a passage in the member iii into an annular recess 45 'which is joined to a return port 45. The second stage 'pump is provided `:Fluid from the bottom of the chamber through aninlet port 5.a' formed in the plate 26. Fluid discharged the 'second stage. passes through an outlet port .5| (Fig. 3) which communicates: with a valve chamber 52.

In the form of the invention .illustrated herein, the casing part l has an appendage portion 65 provided with a transversely extending bore The valve chamber 52 is formed in this bore between the adjacent end of an end cap 52, which is screw-threaded into one end of the bore, and a sleeve member 63 which is inserted into the central portion of the bore. The end cap 62 contains a discharge port Sli. A hollow piston Valve 55 is slidably mounted in the sleeve 63 so that the operative end 56 thereof will be subjected to the fluid in the valve chamber 52. This valve is held seated to close the discharge port 54 by means of a coiled spring 51 which is positioned W'thin the hollow piston valve. A cap member 6B screw-threaded in the other end of the bore tl carries a screw deviceg, the free end of which engages seated against the adjacent end of the spring 61 to provide for adjusting the pressure of the spring on the piston valve and thereby the fiuid pressure at which the valve opens. Preferably, a removable closure 1| is threaded on the cap 65 to seal the return pressure which may cause leakage past the screw threads as Well as to protect the adjusting screw device 69 and facilitate access thereto to permit inserting a screw driver to turn the screw device.

In order to by-pass excess iiuid, the piston valve 55 is also arranged to uncover a by-pass port 12 which is formed in the sleeve 63 and. communicates with the annular recess 45 formed around the sleeve 63. The sleeve 63 is provided with a longitudinal slot 13 opening at one end into the valve chamber 52. Communication between the valve chamber and the by-pass port 12 is established when the piston 65 is moved 4against the spring to bring an annular groove 1 in the exterior side wall of the piston into a position communicating with both the slot 13 4and the port 12. The annular passage 45 communi- Cates with the return or by-pass port 45 which is closed by a plug 15 at its upper end (Fig. l) and communicates at its lower end with the exterior of the casing to provide an external bypass which may be connected to a pipe 1S leading back to the supply tank.

When in use, a pump as illustrated herein may (as shown in Fig. 3) have its inlet port I8 connected to a supply tank 13 by means of a pipe 11 so that fuel oil may be drawn from the supply tank through the pipe 11 and inlet port I8 into the chamber 25. With the pumping device in operation, the first stage pump and second stage pump, through their inlet ports 4U and 55, exhaust the chamber 25 until oil from the tank lls the chamber to the oil level Vas indicated in Fig. 3, thereafter both pumps continue to draw oil from the supply tank into the chamber with the first stage withdrawing excess oil and entrained air from above the oil level and the second stage pump by virtue of its port location drawing only liquid fuel free of entrained air and vapor. The excess oil and air are returned through the port Y113, passage 44, recess 45, port 4B and return pipe 16 to the supply tank 18. With the chamber 20 supplied with oil, the second stage pump receives oil under gravity therefrom through the inlet port 50 and discharges it under pressure to the outlet port 5l which leads to the control valve chamber 52.

A somewhat modified form of circuit is shown in Fig. 4. Many of the features of this circuit are similar to those shown in Fig. 3 and. where such similarity exists similar reference numerals have been employed.

in a cup-shaped memberV The circuit of Fig. 4 is so arranged that the rst stage pump has its inlet 40 bisected by the normal oil level within the reservoir. Inasmuch as a considerable portion of the entrained air accumulates near the surface of the oil in the reservoir a more effective withdrawal of air from the oil can be accomplished by so arranging the inlet 49 with respect to the normal oil level. The discharge port from the first stage pump is connected directly to the tank rather than being added to the excess oil from the second stage pump as in the previous embodiment. The second stage pump is provided with an inlet 50 located at the bottom of the reservoir as previously described and discharges into the valve chamber 22. Excess oil pumped by the second stage is returned by means of the port 45 and a conduit B to the reservoir. Inasmuch as the oil pumped by the second stage is substantially free of entrained air and vapor, it may be returned to the reservoir without fear of contaminating the oil therein. By so arranging the disposition of excess oil pumped by the second stage the amount of oil circulated through the tank is minimized. Thus the total amount of oil circulated by the system is reduced. Like the previously described circuit, the circuit shown in Fig. 4 is one in which both pumps are effective in drawing oil into the reservoir inasmuch as they operate in parallel for this purpose.

When the circuit of Fig. 4 is employed, the discharge port 46 is closed by a plug 8| as shown.

I claim:

l. A two-stage oil burner pump having, in combination, a iirst stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet connection for the rst stage. pumping means communicating with said reservoir at the normal oil level to enable the iirst stage pumping means to Withdraw excess oil and any air above said level, and a discharge connection from the iirst stage pumping means for returnmg excess oil and air to the supply tank.

2. A two-stage oil burner pump having, in

. combination, a first stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank lconnection leading to said reservoir above the normal operating level of the oil, an inlet connection for the first stage pumping means communicating with said reservoir at the normal oil level to enable both pumping means to suck oil from the supply tank to the reservoir and to enable the rst stage pumping means to withdraw excess oil and any air above said level, and a discharge connection from the first Astage pumping means for returning excess oil to the supply tank. V

3. A two-stage oil burner pump having, in combination, a rst stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet connection for the iirst stage pumping means communicating with said reservoir at the normal oil level to enbale the first stage pumping means to withdraw excess oil and any air above lsaid level, a discharge connection from the first stage pumping means, a discharge connection for excess oil pumped by the second stage pumping means and connected to said discharge from the first stage pumping means, and means connecting the discharge from the second stage pumping mean-s to the supply tank.

4. A two-stage oil burner pump having, in combination, a rst stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to -said reservoir, an inlet connection for the rst stage pumping means communicating with said reservoir to enable the first stage pumpingmeans to withdraw excess oil therefrom, and a discharge -connection from the rst stage pumping means for returning excess oil to the supply tank.

5. A two-stage oil burner pump having, in combination, a first stage pumping means, a second stage pumping means, a reservoir to which the inl-et to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet connection for the first stage -pumping means communicating with said reservoir at the normal oil level to enable the rst stage pumping means to withdraw excess oil and any air above said level, a discharge connection from the first stage pumping means for returning excess oil and air to the supply tank, and a discharge connection from the second stage pumping means for returning excess oil pumped thereby to the reservoir.

6. A two-stage oil burner pump having, in combination, a rst stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected bel-ow the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet passage connected to the rst stage pumping means and opening to said reservoir, the opening of said passage being bisected by the oil at normal level in the reservoir to enable the first stage pumping means to withdraw excess oil and any ai-r above said level, and a discharge connection from the first stage pumping means for returning excess oil and air to the supply tank.

7. A two-stage oil burner pump having, in combination, a iirst stage pumping means, a second stage pumping means, a reservoir to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet passage connected to the first stage pumping means and opening to sai-d reservoir, the opening of said passage being bisected by the oil at normal level in the reservoir to enable the first stage pumping means to withdraw excess oil and any air above said level, a discharge connection from the first stage ypumping means for returning excess oil and air to the supply tank, .and a discharge connection from the second stage pumping means for returning excess oil pumped thereby to the reservoir.

8. A two-stage oil burner pump having, in combination, a casing, a first stage pumping means in the casing, a second stage pumping means in the casing, a reservoir in the casing to which the inlet to the second stage pumping means is connected below the level at which the oil stands during normal operating conditions, a supply tank connection leading to said reservoir above the normal operating level of the oil therein, an inlet connection for the first stage pumping means communicating with said reservoir at the normal oil level to enable the iirst stage pumping means to withdraw excess oil and any -air above said level, a pressure operated burner shutoff valve connected to the outlet of the second stage pumping means, means controlled by the valve for bypassing excess fluid pumped -by the second stage pumping means, and a passage connecting the bypass means to the reservoir to return thereto such excess uid.

WILLIAM RAY KIEFER.

References Cited in the i'lle of this patent UNITED STATES PATENTS Number Name Date 1,623,083 Ames Apr. 5, 1927 1,823,459 McCarthy Sept. 15, 1931 1,971,775 Durdin, Jr. Aug. 28, 1934 2,277,977 Hesse Mar. 31, 1942 

